It's a very simple thing to change the coolant in an All-in-One cooler... provided it is not a CLC. CLC characteristics include:
a) Weak pump, typically 0.11 gpm
b) Can not open system to change coolant, augment corrosion inhibitors, etc when they lose their effectiveness after 12-18 months
c) cheap, inefficient aluminum radiators
d) extreme speed fans
e) no reservoir
I would suggest that you get a cooler with none of these weaknesses and grab a Swiftech or EK All-in-One liquid cooler. Changing the fluid is a very simple and easy procedure....as is adding more blocks to the loop, say to cool your GFX card as the pumps are more than capable on these OLC type coolers.
http://www.swiftech.com/aio.aspx...